US 7309048 B2
A vision system and method for use on a refueling tanker to assist a boom operator in performing an airborne refueling operation on a receiver aircraft. The system includes a digital camera system, a sensor subsystem and a processing system that receives information from the sensor system and the camera system. The processing system includes video processing capability and a graphics generator that generates a two dimensional graphics symbology set that is displayed on a display terminal along with a real time image of the boom and the receiver aircraft. The graphics symbology set includes a plurality of graphic symbols that indicate the position of the refueling boom and the position of the receiver aircraft relative to a desired contact zone within which physical contact between the boom tip and a refueling receptacle on the receiver aircraft can be made. The graphics symbology set also makes use of various colors to indicate warning conditions to the boom operator.
1. A refueling vehicle having a refueling boom engageable with a refueling receptacle of an airborne receiver vehicle during an airborne refueling operation, the refueling vehicle comprising:
a monitoring system for monitoring a position of said boom relative to a portion of said refueling vehicle;
a processing system for processing information from said monitoring system and for generating graphical information relating to a position of said boom relative to said receiver vehicle;
a display system responsive to said processing system displaying a graphics symbol set illustrating in graphical format a position of said boom relative to said receiver vehicle to assist an operator in performing said airborne refueling operation, said graphics symbol set including:
a contact zone graphic representing a contact zone within which contact between said refueling boom and said refueling receptacle can be made;
a receiver symbol linearly aligned with said contact zone graphic and movable linearly to indicate a relative distance between said refueling receptacle and the contact zone;
a boom symbol linearly aligned with said contact zone graphic and moveable linearly to indicate a relative distance between a free end of the boom and the contact zone; and
wherein a position of said receiver symbol and said boom symbol both within said contact zone indicates that engagement of said refueling boom and said fuel receptacle can be made.
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10. An aerial refueling system for use on an airborne refueling vehicle, for facilitating engagement between a refueling boom of the refueling vehicle and a refueling receptacle of an airborne receiver vehicle during an airborne refueling operation, the system comprising:
a monitoring system for monitoring a position of said boom relative to a contact zone with which a refueling operation on said receiver vehicle can be accomplished;
a camera for imaging said boom and said receiver vehicle;
a processing system for processing information from said monitoring system and said camera, for generating graphical information relating to a position of said boom relative to said refueling vehicle;
a display system displaying, in real time:
a graphic symbol of said contact zone;
a graphic symbol of said receiver vehicle; and
a graphic symbol of said refueling boom, scaleable in dimension in accordance with a telescoping length of said refueling boom, and being linearly aligned on said display system with said graphic symbol of said receiver vehicle; and
said graphic symbols of said refueling boom and receiver vehicle moving relative to said contact zone graphic symbol as an airborne refueling operation is performed to provide a two dimensional representation to a boom operator of the positions of said refueling boom and said receiver vehicle, relative to said contact zone, to assist in performing said airborne refueling operation on said receiver vehicle.
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15. A method for assisting an individual in an airborne refueling tanker in refueling an airborne receiver vehicle, comprising:
providing a display system;
monitoring a position of a refueling boom extending from said refueling vehicle and a position of a refueling receptacle of a receiver vehicle approaching the refueling vehicle;
generating a graphic symbol representing said refueling boom on said display system and a position of said refueling boom relative to said refueling vehicle;
generating a graphic symbol representing said receiver vehicle on said display system and a position of said receiver vehicle relative to said refueling boom;
said graphic symbol of said refueling boom being scaleable in dimension in accordance with a telescoping length of said refueling boom, and further being linearly aligned on said display system with said graphic of said receiver vehicle; and
using said symbols to visually indicate when said refueling boom and said receiver receptacle are positioned within a predetermined area in which contact can be made between said boom and said refueling receptacle.
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flashing said receiver vehicle symbol on said display system if said receiver vehicle is approaching said contact zone at a speed that exceeds a predetermined maximum closure speed.
This application is related to concurrently filed application, U.S. Ser. No. 11/193,667, entitled “Graphical Symbology Apparatus For Use In An Airborne Refueling System” (Boeing reference no. 05-0659 VDD/HDP reference no. 7784-000869).
The present invention relates to refueling systems used in tanker aircraft for providing airborne refueling to a receiver aircraft, and more particularly to a vision system and method incorporating a two dimensional graphics symbology set for assisting a boom operator in aligning a refueling boom with a refueling receptacle on a receiver aircraft.
Present tanker aircraft typically rely on three dimensional (3D) visual or stereo vision systems that are used by the boom operator to judge distance and closure rates between the receiver aircraft and the refueling boom and/or refueling hose/drogue. Creating an observation window for real vision or implementing a stereo vision system to provide sufficient depth perception, such as a 3D vision system, can be expensive. Three dimensional vision systems require complex, multiple cameras and video processing systems. While some systems have proven effective for their intended use, it would nevertheless be desirable to provide a system that does not require the use of multiple camera, but instead a system that can be implemented using a single camera that provides a two dimensional picture of the receiver aircraft to the boom operator.
It would further be desirable if some graphical system could be employed in connection with a two dimensional image of the receiver aircraft and refueling boom to better enable a boom operator to judge the position and closing speed of the receiver aircraft during an airborne refueling operation.
The present invention is directed to a vision system for use on an airborne refueling tanker vehicle that does not require multiple cameras to provide a stereo vision image for a boom operator performing a refueling operation on a receiver vehicle.
In one preferred form the system of the present invention makes use of a sensor system that provides information on the position of the refueling boom, as well as the position of a fuel receptacle on a receiver vehicle, to a processing system. A single (i.e., mono) camera is used to image the receiver vehicle during the refueling operation. The processing system also generates, from the sensor system, a graphics symbol set that is displayed on a display system used by the boom operator. The same display system may be used for displaying the image generated by the camera on the tanker vehicle. The graphics symbol set includes a graphics symbol representing the boom, a graphic symbol representing a receiver vehicle, and a graphic symbol representing a desired contact zone within which coupling of the boom tip and the fuel receptacle on the receiver vehicle can be achieved. The information on the position of the boom and the position of the receiver vehicle is monitored by the sensor system and information is generated in real time so that the display of the graphics symbol set essentially provides a real time indication of the position of the boom relative to the refueling receptacle on the receiver vehicle.
In one preferred embodiment the graphics symbol set comprises a contact zone graphic, a foundation graphic representing lead-in areas to the contact zone, a refueling boom graphic and a receiver vehicle graphic. In one preferred implementation the contact zone graphic and the refueling boom and receiver vehicle graphics are longitudinally aligned along a common line or axis. Information from the camera system is processed and the positions of the refueling boom graphic and the receiver vehicle graphic are updated to indicate the changing relative positions of these components relative to the contact zone graphic. When the receiver vehicle graphic moves within the contact zone graphic, then the receiver boom can be telescopically extended into the contact zone to couple to the refueling receptacle of the receiver vehicle.
In one preferred implementation different colors are used for the contact zone graphic, the receiver graphic and the boom graphic. Optionally, the receiver graphic can be made to flash repeatedly in the event the sensing system detects that the receiver vehicle is approaching the contact zone at an excessive closure rate.
In another preferred implementation a receiver elevation lead-in graphic is generated and displayed on the display system adjacent to the receiver graphic symbol. When the receiver vehicle is at the proper elevation relative to the refueling vehicle, the lead-in graphic will be contacting the receiver graphic. But if the receiver vehicle is above the predetermined optimum elevation for contact between the boom and the refueling receptacle to occur, then the receiver graphic will be positioned above the elevation lead-in graphic. Conversely, if the receiver vehicle is below the elevation at which the vehicle needs to be at for proper contact to be made, then the elevation lead-in graphic will be positioned somewhere above a lower edge portion of the receiver graphic. In this manner the boom operator can visually discern, at a glance, the position of the receiver vehicle relative to the predetermined elevation at which contact needs to be made between the boom and the refueling receptacle.
In another preferred implementation a color is used with the receiver graphic to designate when the refueling receptacle of the receiver vehicle is in contact with the tip of the refueling boom, but where the refueling receptacle is positioned either excessively forwardly or excessively rearwardly of the contact zone. In this manner the boom operator can inform the operator of the receiver vehicle by RF communications that either greater or lesser separation between the receiver and tanker vehicles needs to be achieved.
In still another preferred implementation of the present invention a boom aim point graphics symbol can be provided on the display system to provide the boom operator with an indication of where the tip of the boom would contact on the refueling vehicle if the boom was to be telescoped to its fully extended length. The boom aim point symbol is projected over the image of the receiver vehicle being provided by the camera. The operator controls the boom to maintain the boom aim point graphic symbol directly over the refueling receptacle on the receiver vehicle while the boom is being fully telescoped.
The features, functions, and advantages can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
With further reference to
A suitable digital camera system for use with the present invention is commercially available from Dalsa Corp. of Waterloo, Ontario, Canada. The boom position sensor subsystem 34 comprises a plurality of sensors that are used to detect the position of the boom 14 relative to the tanker aircraft 12. Suitable boom position sensor systems are disclosed in U.S. Pat. Nos. 6,651,933; 6,752,357; and 6,837,462, owned by the Boeing Co. and hereby incorporated by reference into the present application. Various suitable boom position sensors (e.g., LVDT/RVDT transducers) and sensing subsystems are also widely commercially available. Additional U.S. patents owned by the Boeing Co., which relate to various components of refueling booms and/or tanker refueling systems, and which are all hereby incorporated by reference into the present application, are: U.S. Pat. Nos. 4,586,683; 4,298,176; 5,996,939; 5,785,276; 4,792,107; 4,633,376; 4,519,560; 4,264,044; 4,231,536; 4,160,534; 4,158,885; 4,129,270; 4,095,761; 4,072,283; and 4,025,193.
The processing system 40 may comprise any suitable processor capable of processing the information from the position sensor subsystem 34 and the digital camera system 36 to provide real time information that the graphics generator 42 can use to generate the graphics symbology set 44 that is displayed on the display system 46. The computer 48 may comprise a personal computer or any other suitable form of computer having a suitable video card and processing power able to display the real time images generated by the digital camera system 36 and the graphics symbology set 44.
Referring further to
In each of the graphs 50, 52 and 58, colors may be employed to assist the operator in aligning the boom 14. The color green indicates normal operating limits of the boom 14.
Referring further to
The receiver aircraft symbol 64 is preferably also colored with a unique color, in this example grey, and is preferably outlined in a different color, for example a yellow band 72. A horizontal dashed line 74 is also provided that represents a “receiver elevation lead-in” line for indicating an optimum receiver aircraft elevation as the receiver aircraft 16 moves forward and aft within the refueling region at the rear of the tanker aircraft 12. The elevation line 74 will move up and down relative to the receiver symbol 64 to indicate the position of the refueling receptacle 18 lead-in relative to the optimum contact point elevation within the contact zone 20. The lower edge of the receiver symbol 64 touching the elevation lead-in line 74, as shown in
With reference to
While the graphics symbology set 44 has been illustrated as a plurality of rectangular symbols aligned along a vertical axis, it will be appreciated that the symbols used could vary widely in size and shape. Any symbols that enable an immediate visual representation to be provided as to the positions of the receiver aircraft 16, the lead-in areas leading to the contact zone, and the contact zone itself, can be used. The use of various colors also aids the boom operator by providing immediate visual cues of undesired or dangerous conditions developing during the refueling operation.
It will also be appreciated that the sensors needed for sensing the distance of the receiver aircraft 16 relative to the contact zone 20, could be provided by a variety of systems. For example, distance sensing between the receiver aircraft 16 and the contact zone 20 can be accomplished by information gleaned from the camera system 36, as described in connection with
With specific regard to the boom 14 separation distance from the refueling receptacle 18, one alternative enhancement would be the use of a boom extension distance sensor signal which would be processed to show, on display system 46, an absolute distance between the boom tip 26 and the optimum contact point in the contact zone 20 behind the refueling tanker 12 for boom contact to occur with the refueling receptacle 18. Still further, another alternative enhancement could be using the boom symbol 66 to display a number inside of it that represents an actual distance between the boom tip 26 and the nearest point on the surface of the receiver aircraft 16. In this instance the actual boom 14 extension distance would be implied by its contact with the refueling receptacle 18. In the absence of a refueling receiver 18 in position to receive the boom tip 26, the boom symbol 66 would not be used to judge the boom extension length relative to the optimum contact point. In this case boom 14 extension distance would be monitored via reference to a telescoping distance scale as shown in
The system and method of the present invention thus provides a means for providing a boom operator with a graphics symbology set that enables a plurality of important conditions to be presented in an easy to comprehend visual format, to thus aid the boom operator during a refueling operation. The graphics symbology set 44 also can be used to provide various warnings, in different colors, to instantly alert the boom operator that an undesired condition has developed, as well as what corrective action needs to be taken either by the boom operator or by the pilot of the receiver vehicle 16. The system and method of the present invention can be integrated for use with a variety of refueling tankers and with a relatively small number of independent components, and in some instances may even use existing sensor systems already present on a refueling tanker.
While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.